There's much structure in the ENSO model phase plots

By multiplying the points by the strength of the annular impulse at that time, the phase-plots give away the source of the alignment

Leading month pulse:
![](https://imagizer.imageshack.com/img924/6004/xXSmHF.png)

Trailing month pulse:
![](https://imagizer.imageshack.com/img924/1685/9jsZGd.png)

There's also a 3-D quality to these plots, akin to a skewed perspective view of a box. This exercise is essentially one of extracting a geometric order out of once was a seemingly erratic time-series.


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The erratic translation of the squared contours is due to a square wave that's staggered by a primary tidal cycle which is incommensurate with the annual impulse. IOW, if the sine wave and the annual impulse were the same period, a lagged impulse response would create a perfect square wave, not one that looks like this

![](https://imagizer.imageshack.com/img924/9279/yXZ6UM.gif)